
https://blogs.lse.ac.uk/brexit/2020/02/21/migration-how-scotland-hoped-to-do-things-differently/

http://library.fes.de/pdf-files/bueros/budapest/15322-20190505.pdf

http://www.cesifo-group.de/ifoHome/publications/working-papers/CESifoWP/CESifoWPdetails?wp_num=6441&CESifoWP.search=+